(1) Field of the Invention
This invention relates to underwater vehicle polymer ejection control valves and is directed more particularly to an assembly including Such a control valve and a valve actuator responsive to changes in water pressure to automatically open and close the valve.
(2) Description of the Prior Art
It is known that ejection of a polymer from a forward portion of an underwater body, as the body travels through a water environment, causing the polymer to stream along the exterior surfaces of the body, has a salutary effect upon quiet running of the underwater body through the water.
In furtherance of the study of the effects of fluid polymers ejected from underwater bodies onto the exterior surfaces of the body, test vehicles have been utilized which are buoyant and adapted to travel, by virtue of their buoyancy, from a selected depth in a column of water, typically in a protected natural body of water having a depth of 1100 feet, or more, to the surface of the water. Such buoyant test vehicles (BTV) are provided in which a drag reducing polymer is ejected from the nose of the BTV so as to coat the hull of the BTV with polymer as the BTV travels through the water. The polymer typically is ejected by compressed air expanding in a housing holding liquid polymer, forcing the polymer out of the housing and out ejection ports in the BTV hull. Once the known ejection process is begun, it continues until all the polymer has been ejected.
It now is known that polymer flow rates sufficient to achieve the desired effect are quite small. By providing a valve assembly having facility for turning the polymer flow on and off at appropriate times, the amount of polymer on board the BTV can last through two or three runs of the BTV before requiring a refill.
Thus, there is a need for a BTV having a polymer ejection control valve assembly which operates to turn the ejection control valve on and off at preselected points in the travel of the BTV, so as to conserve polymer and thereby reduce time spent refilling the polymer reservoir.